The present invention relates to a modular transceiver system and to identifying the modules therein. It particularly but not exclusively relates to a self configuring modular transceiver system which identifies the functionality of the attached modules.
A mobile radio telecommunications network consists of at least one base station and a plurality of mobile stations. The mobile stations communicate with each other via the base station. The base station includes a base transceiver system which has at least one transceiver for communication with transceivers in the mobile stations. It is desirable for base transceiver systems to be adaptive so that end users can optimise the system for their needs. For example where there is considerable signal attenuation it may be desirable to boost the signal by providing a booster circuit within the base transceiver system, while where there is considerable traffic it may be preferable to include a second or third transceiver instead of the booster circuit. It is therefore desirable to market base transceiver systems as modular systems which can be modified or upgraded by the replacement or addition of functional modules. However, a base transceiver system is a complex collection of functional units and the successful aggregation of these units is a skilled and difficult task. It would be desirable if the base transceiver system was self-configuring. The end user could then simply attach the requisite functional modules to the base transceiver system and the system would configure itself to obtain a working system of the desired functionality.
According to one aspect of the present invention there is provided a functional module for connection in a modular transceiver system in a radio communication network operating at an RF frequency within a RF frequency range, comprising:
an input for receiving input signals at the RF frequency;
an RF signal processor connected to said input for receiving and processing said input signals;
an ID generating circuit for generating an identification signal characterising the functional module; and
an ID port for transmitting the identification signal to an interrogation circuit in the transceiver system.
The functional module can be, for example, a power amplification module such as a booster module or a filter module.
The invention also provides a self-configuring transceiver module, for use in a modular transceiver system of a radio communication network operating at an RF frequency within an RF frequency range, the transceiver module comprising:
an RF unit for generating and receiving RF signals in the RF frequency range;
an ID port for receiving an identification signal from a connected functional module, said identification signal characterising said functional module; and
detection circuitry for identifying the nature of the functional module from the identification signal and for configuring the transceiver system in response thereto.
This allows the transceiver module to automatically configure the transceiver system in accordance with the functional module which is connected thereto. Thus, there is no need for a user manually to determine the type of module being inserted into the modular transceiver system because the self-configuring transceiver module will automatically configure the transceiver system appropriately in accordance with the functional module which is connected.
The invention also provides in another aspect a method for automatically identifying a functional module in a modular transceiver system, said system operating within an RF frequency range, the method comprising the steps of:
supplying to the functional module a checking signal at a checking frequency outside said RF frequency range;
measuring the response of said functional module at said checking frequency, said response being characteristic of the nature of the functional module; and
identifying the nature of the functional module on the basis of said response, and configuring the transceiver system accordingly.
This method allows the functional module to be identified by interrogation at a checking frequency, which, in the preferred embodiment, is d.c. However, the checking frequency need not be d.c. but could be a frequency which is significantly lower than the RF frequency, for example a {fraction (1/10)} or {fraction (1/100)} of the RF frequency.
A power source for the identification signal can either be included within the functional module or within the transceiver module. Where the power source is provided within the functional module the ID signal may be a voltage level, a current level or a serial data stream.
In the particularly preferred embodiment, a duplex connector in the form of a coaxial cable provides the input for receiving the RF signals and the identification port for transmitting the identification signal. This is made possible if the identification signal is at a frequency outside the RF frequency range, and preferably significantly lower than the RF frequency. The ID signal and the input signals can then be separated by a choke and capacitor arrangement within the functional module, and a similar such arrangement in the transceiver module.
The invention has particular benefit in a situation where the transceiver module has a power control loop which uses a fed-back detected power level from the output RF signal. The configuration of the power control loop has one arrangement in the presence of a filter module and a different arrangement in the presence of a booster amplifier module.
In an existing transceiver module, a peak power detector which is an element of the power control loop is located within the transceiver module. When a booster module is connected to the output of the transceiver module, a separate peak power detector within the booster module should be configured within the power control loop. Thus, the remaining power control circuitry within the power control loop of the transceiver module should use the output of the peak power detector in the booster module instead of the peak power detector in the transceiver module. As described in our earlier British Patent Application No. 9706423.2, this can be accomplished by means of a switch.
The above described aspect of the present invention enables this switch to toggle automatically upon detection of the presence of a booster module, and thus removes the need for operator intervention if a module based transceiver system becomes upgraded to utilise a booster module. It also has the benefit of standardising the transceiver module.
For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made by way of example to the accompanying drawings.